1. Field of the Invention
The invention relates to burglar alarm systems, and more particularly to an annunciator system which provides a visual indication of the status of each individual access switch contained in a burglar alarm system.
2. Description of the Prior Art
Burglar alarm systems generally include a power supply, one or more audible alarm units, a plurality of contact switches or access switches located to detect opening of doors, windows or the like. The contact switches or access switches are interconnected to each other and are also connected to a burglar alarm sensing unit. One type of system, referred to as a closed loop circuit burglar alarm system, is commonly utilized, wherein electric current of a predetermined level flows through all of the access switches, which are connected in a series, and which are normally in a closed position when the automatic burglar alarm system is "armed" and is "guarding" the premises in which the burglar alarm system is installed. When a door, window or the like is opened or an intruder steps on a switch concealed in hallway carpet or the like, a corresponding one of the normally closed access switches is opened, interrupting the predetermined current level. The burglar alarm sensing system detects the interruption of the current level and causes the audible alarm unit to sound.
Before a burglar alarm system is "armed" (so that it will emit an alarm sound or signal if a normally closed access switch is opened) it is necessary to know if all of the access switches are properly closed, since if the burglar alarm system is armed with one or more of the access switches opened, the burglar alarm set will be "set off" or actuated, causing the alarm to sound. For a premises with a large number of access switches, the task of determining the status of each individual access switch can be time consuming and therefore costly. Some known burglar alarm systems include annunciator panels which are centrally located in a premises, which annunciator panels include display lights to indicate the presense of an open access switch within a predetermined "zone". Each such "zone" includes a plurality of access switches. U.S. Pat. No. 3,689,906 discloses such a system. Other known systems include display lights located at or near each individual access switch, each such display light indicates whether the corresponding nearby particular access switch is opened or closed. U.S. Pat. No. 3,924,256 discloses such a system. If it is determined that all of the access switches in prior burglar alarm systems are not closed, it is then necessary for an operator to inspect each access of the premises to be sure that all entries, and hence all access switches, of the premises are closed before activating the burglar alarm system. There clearly is an unmet need for an annunciator system which enables an operator to determine at a glance whether all access switches in a burglar alarm system are in their proper state or configuration before arming the burglar alarm system, to alleviate the need of having to actually inspect each entry or access to the premises.
Accordingly, it is an object of the invention to provide an annunciator system which enables an operator to determine at a glance which access switches in a burglar alarm system are open and/or closed.
The circuitry, wiring, and status indicators systems of most prior burglar alarm systems and annunciator systems associated therewith are very complex and costly.
Accordingly, another object of the invention is to provide a simple, low cost annunciator system for burglar alarm systems.
Since many prior burglar alarm systems which have already been installed do not have a satisfactory annunciator system which can be easily incorporated into pre-existing annunciator systems.
Another object of the system is to provide a low cost annunciator system which can be inexpensively and simply connected to a previously installed burglar alarm system.
A novelty search directed to the present invention uncovered the following U.S. Patents in addition to the two mentioned above: U.S. Pat. Nos. 3,821,733; 3,696,374, 4,015,256; and 2,971,186.
It is another object of the invention to provide an annunciator system for use in conjunction with alarm and/or monitoring systems, which annunciator system overcomes the shortcomings of the known prior art.